Patent Application
20100050587
The present invention is directed to a modular sickle bar having an improved locking system. The sickle bar is comprised of modular cutting sections bolted together and then locked together with use of an integrated locking system having a protrusion on one surface of a modular knifeback and a mating depression to receive the protrusion on the opposite surface of another modular knifeback and to secure such sections thereto.
Considerable crop cutting is performed by combines and other crop cutting machinery. During operation, standing plant material, such as a crop, is pushed by a reel against a cutter bar and then onto a platform, where the cut crop is conveyed toward the center of the platform from either side by the platform auger or belt and then subjected to further harvesting operations. Cutting of the crop is performed by a sickle-type cutting system and method in which a reciprocating knife and stationary countershear (rock guards) cut the crop material between the knives and knife guards in a slicing action. Sickle-type cutting systems and methods are old and well known in the art and remain a predominant cutting technique for combine headers and other crop cutting equipment.
As the width of modern harvesting headers continues to increase, problems, such as increased breakage, associated with the knifeback are created. Breakage is believed to be associated with increased stress and strain forces of the reciprocating cutting system. The magnitude of these forces continues to increase as the length of cutting systems increases and faster reciprocation of the sickle bar is attempted. Thus there is a continuing need in the industry for a stronger, more fatigue resistant knifeback.
The art has utilized modular sickle bars to attempt to ease in the handling and shipment of replacement sickles, but these don't do anything to increase the strength and the fatigue resistance of the sickle bar. The modular sickle bar design of this invention can do both. Such systems are exemplified by U.S. Pat. Nos. 4,805,390; 4,854,114; 4,942,728; 5,040,363; 5,161,357; and 6,886,316.
The art has also utilized locking systems to lock modular sickle bar sections in place. In this regard, see Gebrauchsmuster Number DE 295 11 586 U1 and German Patent Number DE 195 26 191 C2 where a tongue-in-groove locking system is described. Such locking system restrains relative movement of the joined sections in a vertical direction with respect to the ground when the crop harvesting header is in use.
When compared with the tongue-in-groove system described above, the use of the locking system of the present invention results in improved structural integrity of the knifeback assembly because such system locks the modules together in planes parallel and perpendicular to the longitudinal axis of the knifeback portion of the sickle bar.
The present invention generally comprises a sickle bar for mounting a plurality of adjoining sickle cutting sections along the length of the bar. The sickle bar includes a knifeback having a longitudinal axis and having top and bottom modular bar assemblies, including at least two modular bars arranged end-to-end to form a knifeback. A plurality of sickle cutting sections are located side-by-side along the knifeback and against one of said bar assemblies and have holes extending through the sections. A fastener extends through the holes in said sickle cutting sections thereby joining together said sickle cutting sections and said top and bottom modular bar assemblies. A locking system having a protrusion on one surface of a first modular cutting section and a mating depression(s) to receive and secure the protrusion(s) on an opposite surface of a second modular cutting section wherein, as oriented with respect to the ground when the cutting system is in use, movement of said first and second cutting sections is restrained in all linear planes parallel to the longitudinal axis of the knifeback and in a plane perpendicular to such axis.
The present invention utilizes a modular sickle bar having a plurality of cutting sections fastened together, such as by bolting, and then locked together with use of a locking system which restrains relative movement of the joined sections along planes parallel to and perpendicular to the longitudinal axis of the knifeback when the crop harvesting header is in use.
The locking system of the present invention functions to improve the structural integrity of the knifeback assembly because it locks the modules together in planes of potential movement. In other words, as oriented with respect to the ground when the cutting system is in use, movement is restrained in all linear planes, including those along the longitudinal axis of the knifeback and perpendicular to such axis.
First, like the tongue and groove system described above, the upper and lower knifeback modules are secured or held together relative to each other on the forward to rear (side to side) plane. Securing by only locking in this manner tends to align the upper and lower modules, but does not materially strengthen the actual joint itself in the manner achieved by the present invention.
Second, a second plane of motion is achieved by keeping the entire assembly straight during the assembly process by locking in two holes per each module, thereby locking the knifeback in a permanent straight line. This arrangement assists in keeping the modular knife back inline along its entire length, thus assisting in keeping the modular knifeback inline while shipping to the user and during installation.
Third, the third plane of movement can be described as the potential of linear movement between modules while the sickle is in motion. In operation, the sickle is operated from only one end and is driven to-and-fro at a high rate of speed thereby causing extreme linear stress and strain at the joint areas. Modular sickles of the prior art rely completely on the proof load of the bolted joint to keep them together. The joint in this invention is locked from any sort of movement because the protrusions are virtually press fit into the mating depression. Such press fit is exposed to the brunt of these extreme forces, not the bolted joint. Hence, harmful and costly failures due to bolt failure are reduced and minimized by the present invention. Linear movement of the modular sections under load along a plane parallel to the longitudinal axis of the knifeback and parallel to the ground leads to excessive wear and breakage of the fastening element and ultimate failure of the knifeback. The movement restraint described above is achieved by the present invention but not by the above-described tongue and groove locking system. Such improved movement restraint is achieved by the integrated locking system of the present invention which utilizes a locking arrangement having a protrusion(s) on one surface of a modular cutting section and a mating depression(s) to receive the protrusion on the opposite surface of another modular cutting section.
The present invention is more completely described and explained by reference to the following drawings.
Suitable modular sickle cutting sections may typically be manufactured from high strength steels, including 1035 to 1090 carbon steels; boron steels, including 10B20 to 10B52, alloy steels, including 4140, 4150, and 4160; and tool steels, including O-1, A-2, D-2, and M-4. These steels are typically heat-treated to hardness levels of from about 25 to about 65 on the Rockwell C scale. A typical heat treatment comprises quenching and tempering by following practices and parameters known in the art for such steels.
